Average weight of a DNA basepair (sodium salt) = 650 daltons

1.0 A₂₆₀ unit ds DNA = 50 µg/ml = 0.15 mM (in nucleotides) 
1.0 A₂₆₀ unit ss DNA = 33 µg/ml = 0.10 mM (in nucleotides) 
1.0 A₂₆₀ unit ss RNA = 40 µg/ml = 0.11 mM (in nucleotides)

MW of a double-stranded DNA molecule = (# of base pairs) X (650 daltons/base pair) 
Moles of ends of a double-stranded DNA molecule = 2 X (grams of DNA) / (MW in daltons) 
Moles of ends generated by restriction endonuclease cleavage: 
a) circular DNA molecule: 2 X (moles of DNA) X (number of sites) 
b) linear DNA molecule: 2 X (moles of DNA) X (number of sites) 2 X (moles of DNA)

1 µg of 1000 bp DNA = 1.52 pmol = 9.1 X 10¹¹ molecules 
1 µg of pUC18/19 DNA (2686 bp) = 0.57 pmol = 3.4 X 10¹¹ molecules 
1 µg of pBR322 DNA (4361 bp) = 0.35 pmol = 2.1 X 10¹¹ molecules 
1 µg of M13mp18/19 DNA (7249 bp) = 0.21 pmol = 1.3 X 10¹¹ molecules 
1 µg of λ DNA (48502 bp) = 0.03 pmol = 1.8 X 10¹⁰ molecules

1 pmol of 1000 bp DNA = 0.66 µg 
1 pmol of pUC18/19 DNA (2686 bp) = 1.77 µg 
1 pmol of pBR322 DNA (4361 bp) = 2.88 µg 
1 pmol of M13mp18/19 DNA (7249 bp) = 4.78 µg 
1 pmol of λ DNA (48502 bp) = 32.01 µg

1.0 kb DNA = coding capacity for 333 amino acids @ 37,000 dalton protein 
10,000 dalton protein @ 270 bp DNA 
50,000 dalton protein @ 1.35 kb DNA